Friday 20 May 2011

Sex Chromosome Variation in Denmark

A 20 year old study - but still good science.
Sex Chromosome Abnormalities Found Among 34,910 Newborn Children: Results From a 13-Year Incidence Study in Århus, Denmark J.Nielsen and M.Wohlert in Birth Defects: Original Article Series, Volume 26, Number 4, pages 209-223
Chromosome examination was made of 88% (34,910) of all 39,618 live- born children at the Maternity Hospital in Århus during a 13-year period from 1969 to 1974 (4 years, 5 months) and from 1980 to 1988 (8 years, 7 months).

This paper deals only with the sex chromosome abnormalities. Autosomal abnormalities will be presented elsewhere.

Klinefelter syndrome was found in 1 per 596 boys, XYY in 1 per 894 boys, triple X in 1 per 1002 girls, and Turner syndrome in 1 per 2130 girls. Other sex chromosome aberrations were found in 1 per 11,637 children. The total incidence of sex chromosome abnormalities was 1 per 448 children or 2.23 per 1000.

KaryotypeNumber
47,XXY20
46,XY/47,XXY7
46,XX(male)2
48,XXYY1
47,XYY18
46,XY/47,XYY2
47,XXX17
45,X1
45,X/46,XX2
45,X/47,XXX1
45,X/46,X,r(X)1
45,X/46,X,inv(X)**1
45,X/46,X,i(Xq)/47,X,i(Xq),i(Xq)1
45,X,inv(9)/46,XX,inv(9)1
45,X/46,XY (male)1
46,XX/ 47,XX,del(Yq) (female)1
46,XX/46,XY (female)1
Total78
What was that about "boys are 46Xy, girls 46XX, and the others only one in a million" again?

Of course most Intersexed children don't have such obvious chromosomal variation from the norm. 1 in 500 girls have Congenital Adrenal Hyperplasia(CAH). Then there's those with Persistant Mulleriam Duct Syndrome(PMDS), Complete Androgen Insensitivity Syndrome(CAIS), Partial Androgen Insensitivity Syndrome of various degrees (PAIS), 5-alpha-reductase-2 deficiency syndrome (5ARD), 17-beta-hydroxysteroid-dehydrognase-3 deficiency syndrome (17BHDD), 3-beta-hydroxysteroid-dehydrognase-3 deficiency syndrome (3BHDD) which can also cause CAH, Vaginal Dysgenesis, Gonadal Dysgenesis, and so on and so on, from minor mutations, environmental causes, or timing glitches.

None of those are counted in the above.

1 comment:

Annie said...

I appreciate you posting these summaries. I don't have much of an idea of what's in the literature out there.